Top 10 pratfalls for novice Linux admins

If you are new to Linux, a few common mistakes could land you in hot water, says Jack Wallen.

For many, migrating to Linux is a rite of passage that equates to a thing of joy. For others, it is a nightmare waiting to happen. But if you know the most common mistakes new Linux administrators make, you can avoid disaster. Here are 10 of the most frequent Linux errors.

1. Installing applications from various types
This practice might not seem like such a bad idea at first. You are running Ubuntu, so you know the package-management system uses .deb packages. But there are a number of applications that you find only in source form. No big deal?

They install, they work — so why not use them? Simple: your package-management system cannot keep track of what you have installed if it is installed from source. So what happens when package A, installed from source, depends on package B, installed from a .deb binary, and package B is upgraded from the update manager?

Package A might still work, or it might not. But if both package A and B are installed from .debs, the chances of them both working are far higher. Also, updating packages is much easier when all packages are from the same binary type.

2. Neglecting updates
This failing is not confined to Linux and has more to do with poor administration skills. However, many admins get Linux up and running, then think they need do nothing more. It is solid, secure and it works.

New updates can patch new exploits. Keeping up with your updates can make the difference between a compromised system and a secure one. And just because you can rest on the security of Linux does not mean you should.

For security, for new features, for stability — the same reasons we have all grown accustomed to updating with Windows — you should always keep up with your Linux updates.

3. Poor root password choice
Repeat after me: "The root password is the key to the kingdom." So why would you make the key to the kingdom simple to crack?

By all means, make your standard user password something you can easily remember and type. But the root password — you know, the one that is protecting your enterprise database server — merits a much higher difficulty level.

Make that password one you might have to store, encrypted, on a USB key, requiring you to slide the key into the machine, mount it, decrypt the password and use it.

4. Avoiding the command line
No-one wants to memorise a set of commands and, for the most part, the user interface takes care of the majority of them.

But there are times when the command line is easier, faster, more secure and more reliable. Avoiding the command line should be considered a cardinal sin of Linux administration.

You should at least have a solid understanding of how the command line works, and a small arsenal of commands you can use without having to read the manual. With a small selection of command-line tools on top of the user-interface ones, you should be ready for just about anything.

5. Not keeping a working kernel installed
You do not need 12 kernels installed on one machine. But you need to update your kernel, and the update process does not delete previous ones. So what do you do?

You keep at least the most recently working kernel at all times. Say you have 2.6.22 as your current working kernel...